Aperture - the best RAW converter for X-Trans cameras?

Weeeell, not quite, but not far off. There are colour artefacts, as others have observed. However, there is a complete lack of watercolour effect, zipper effect and no extra softness. If you've nailed your exposure, often the results from Aperture will be the most pleasing, particularly at 100%. In any event, this is all a shameless link back to a post on my blog where I deal with this in more detail: http://wp.me/p2wMAg-sO